2010 Primary Sulfur Dioxide (SO2)

National Ambient Air Quality Standard (NAAQS)

Technical Analyses and Information Supporting the

Designation Recommendation for Oklahoma

Modeling Compliance with the 1-Hour SO2 NAAQS

Modeling Report

Prepared by the Engineering Section of the Permitting Unit

Air Quality Division

Oklahoma Department of Environmental Quality

September 8, 2015
Table of Contents

1. WHAT IS THE BACKGROUND FOR THE MODELING? ................................................1

1.1 Which sources are affected sources?....................................................................1

1.2 Which sources will shut down or have proposed to shut down? .......................2

1.2.1 What will happen to the GRDA Grand River Energy Center?...........2

1.2.2 What will happen to the PSO NE Power Station? ..............................2

1.3 Which sources were modeled?..............................................................................3

1.3.1 How was the OG&E Muskogee Generating Station modeled? ..........3

1.3.2 How was the OG&E Sooner Generating Station modeled? ...............3

1.3.3 How was the WFEC Hugo Generating Station modeled? ..................3

2. WHAT MODELING PROGRAMS WERE USED FOR THE MODELING 

ANALYSIS? ...........................................................................................................................3

2.1 What is the recommended air dispersion model?...............................................3

2.2 Was screening modeling used? .............................................................................4

3. HOW WERE THE MODELING DOMAINS ESTABLISHED FOR THE MODELING 

ANALYSES?..........................................................................................................................4

3.1 How were the modeling domains setup?..............................................................4

3.2 How were the receptor grids established?...........................................................5

3.3 What terrain data was utilized for the modeling analyses?...............................6

3.4 What were the domain classifications: rural or urban?.....................................6

4. WHAT SOURCE DATA WAS USED IN THE MODELING ANALYSIS? .......................7

4.1 What are the affected source configurations and source types? .......................7

4.2 What nearby sources were included in the modeling domains? .......................7

4.3 How were intermittent emission sources addressed? .........................................7

4.4 What are the affected source emissions inputs?..................................................7

4.4.1 How were hourly emissions from the affected sources 

determined?.........................................................................................8

4.4.2 What operational data was used from the RATA? .............................8

4.5 How was GEP stack height addressed? ...............................................................9
4.6 Was building downwash included in the modeling analyses? ...........................9

5. WHAT METEOROLOGICAL DATA WAS USED IN THE MODELING 

ANALYSIS? ...........................................................................................................................9

5.1 What meteorological data was used? ...................................................................9

5.2 What surface data was used?..............................................................................10

5.2.1 How were sites from the ISHD evaluated?.......................................10

5.2.2 What is Oklahoma Mesonet data and how is it used? ......................11

5.3 What upper air data was used? ..........................................................................11

5.4 How were surface characteristics of the meteorological sites determined? ...11

5.4.1 What was used to determine the surface moisture conditions? ........12

6. WHAT BACKGROUND MONITORING DATA WAS USED IN THE MODELING 

ANALYSES?........................................................................................................................12

6.1 What background monitoring data is utilized? ................................................12

7. WHAT ARE THE MODELED FACILITY IMPACTS?.....................................................13

7.1 What were the modeled impacts for the domain which included the 

WFEC Hugo Generating Station?......................................................................13

7.2 What were the modeled impacts for the domain which included the 

OG&E Muskogee Generating Station? .............................................................13

7.3 What were the modeled impacts for the domain which included the 

OG&E Sooner Generating Station?...................................................................16

8. WHAT IS THE SUMMARY OF THE MODELING RESULTS? ......................................17

8.1 What areas demonstrate compliance with the 2010 1-hour SO2 NAAQS 

using modeling?....................................................................................................17

8.2 What areas do not currently demonstrate compliance with the 2010 1-

hour SO2 NAAQS using modeling?....................................................................17

8.2.1 What area has potential impacts greater than the 2010 1-hour 

SO2 NAAQS that were predicted under Scenario 1 for the OG&E 

Muskogee Generating Station? .........................................................18

9. WHAT REFERENCES WERE USED?...............................................................................18
APPENDICES

APPENDIX A – FACILITY DOMAINS WITH RECEPTORS

APPENDIX B – LAND USE/LAND COVER AERIAL PHOTOS

APPENDIX C – AERIAL PHOTO OVERLAID WITH FACILITY DATA

APPENDIX D – SOURCE DATA

APPENDIX E – 2012-2014 OKLAHOMA MESONET SITES & ASSOCIATED ISH & ESRL 

STATIONS

APPENDIX F – WIND ROSES

APPENDIX G – SURFACE CHARACTERISTICS
Oklahoma 2010 SO2 NAAQS Modeling Report Page 1

1. WHAT IS THE BACKGROUND FOR THE MODELING?

On June 22, 2010, the U.S. Environmental Protection Agency (EPA) revised the primary sulfur 

dioxide (SO2) National Ambient Air Quality Standard (NAAQS). The EPA promulgated a new 

1-hour annual primary SO2 standard at a level of 75 parts per billion (ppb), based on the 3-year 

average of the annual 99th percentile of the daily maximum 1-hour average concentrations. The 

area designation process typically relies on air quality concentrations characterized by ambient

monitoring data to identify areas that are either meeting or violating the relevant standard. 

However, a hybrid approach using modeling and monitoring for the designation process was 

proposed because of the following:

 SO2 impacts are considered to be “source-oriented” rather than “regional” (peak

concentrations of SO2 are commonly caused by one or a few major point sources in an area 

and peak concentrations are typically observed relatively close to the source);

 Ambient SO2 concentrations can be modeled accurately using well understood air quality 

modeling tools; and

 Only approximately 35% of the monitoring network was addressing locations of maximum 

(highest) concentrations of specific sources or groups of sources.

On March 2, 2015, a Consent Decree (CD) was filed requiring the EPA to sign for publication in 

the Federal Register no later than sixteen (16) months from March 2, 2015, a notice of EPA’s 

promulgation of designations for the 2010 revised primary SO2 NAAQS, pursuant to Section 

107(d) of the CAA, and within ten (10) business days following such signature, deliver the 

notice to the Office of the Federal Register for review and prompt publication, for undesignated 

areas which:

1) Based on air quality monitoring in the three (3) full calendar years preceding such deadline 

have monitored violations of the 2010 revised primary SO2 NAAQS; or

2) Contain any stationary source that has not been “announced for retirement” by the date of 

this Consent Decree, and that, according to the data in EPA’s Air Markets Database, either

a. Emitted more than 16,000 tons of SO2 in 2012, or

b. Emitted more than 2,600 tons of SO2 and had an annual average emission rate of 0.45 

lbs SO2/MMBTU or higher in 2012.

By September 18, 2015, the State of Oklahoma may submit to EPA additional information 

regarding the affected facilities and for which updated air quality analyses have been used to 

characterize the air quality around the source either through monitoring, modeling, or a 

combination of modeling and monitoring.

1.1 Which sources are affected sources?

Based on the consent decree, the following sources are the affected sources:
Oklahoma 2010 SO2 NAAQS Modeling Report Page 2

Table 1.1-1. Affected Sources

Company Facility/Emission Unit County

2012 

Emissions 

(TPY)

Avg. 

Emission Rate 

(lb/MMBTU)

Oklahoma Gas and Electric Muskogee Generating 

Station

Muskogee 22,647

Unit 4 7,356 0.48

Unit 5 7,328 0.47

Unit 6 7,963 0.54

Oklahoma Gas and Electric Sooner Generating Station Noble 15,884

Unit 1 8,591 0.56

Unit 2 7,293 0.49

Western Farmers Electric 

Coop

Hugo Generating Station Choctaw

Unit 1 8,066 0.60

There were two other facilities Grand River Dam Authority (GRDA) Grand River Energy Center

(Unit 1) in Mayes county and Public Service Company (PSO) Northeast (Unit 3313 & Unit 

3314) in Rogers County which had an average emissions rate greater than 0.45 lb/MMBTU but 

which had “announced for retirement” the affected units at their facility prior to March 2, 2015.

1.2 Which sources will shut down or have proposed to shut down?

There are two facilities which are scheduled or anticipated to shut down or cease operations by 

January 1, 2017, or which will limit emissions to below the applicability threshold. These 

facilities and their circumstances are shown in Sections 1.2.1 and 1.2.2.

1.2.1 What will happen to the GRDA Grand River Energy Center?

GRDA has proposed shutting down Unit No. 1 and reducing operation of Unit No. 2. The shut 

down of Unit No. 1 should be completed by April 2016. Construction Permit No. 2009-179-C 

(M-3) was issued on August 21, 2014, authorizing the construction of a natural gas fired 

combustion turbine, installation of activated carbon injection on Unit 2, and either shutting down 

Unit No. 1 or conversion of Unit No. 1 to natural gas by the Mercury and Air Toxics Standards 

(MATS) compliance date of April 2016. Therefore, Unit No. 1 was excluded from the 

requirements of the CD. Unit 2’s average emission rate during 2012 was 0.2 lb/MMTBTU

which is why it was excluded.

1.2.2 What will happen to the PSO NE Power Station?

PSO has proposed shutting down Unit No. 3314 and reducing operation of Unit No. 3313. Permit 

No. 2009-179-TVR (M-5) was issued on November 20, 2013, authorizing the installation of an 

activated carbon injection system on Unit 3313 and either shutting down Unit 3314 or 

conversion of Unit No. 3314 to natural gas by the MATS compliance date of April 2016. The 

shutdown of Unit No. 3314 should be completed by April 2016. Therefore, Unit No. 3314 was 

excluded from the requirements of the CD. By April 2016, Unit 3313 must meet emission limits 

of 0.4 lb/MMBTU which is why it was excluded.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 3

1.3 Which sources were modeled?

There are three affected facilities for which air dispersion modeling was conducted to determine 

impacts and to help with recommendations for the 2010 1-hour SO2 designations. These 

facilities and their circumstances are shown in the following sections.

1.3.1 How was the OG&E Muskogee Generating Station modeled?

OG&E is required by the Regional Haze Program to install Best Available Retrofit Technology 

(BART) on Unit 4 and Unit 5 (40 CFR § 52.1923). OG&E has committed to meeting the federal 

emission limit of 0.06 lb/MMBTU by January 4, 2019, by conversion of Unit 4 and Unit 5 to 

natural gas. Since the conversion will occur sometime in the future, the air quality analyses for 

this facility involved three operating scenarios:

1) Modeling of current actual emissions for Unit 4, Unit 5, & Unit 6;

2) Modeling of Unit 4 using the BART emission limit and Unit 5 & Unit 6 using the 

maximum actual emission rate during 2012 through 2014; and

3) Modeling of Unit 4 & Unit 5 using the BART emission limit & Unit 6 using the 

maximum actual emission rate during 2012 through 2014.

1.3.2 How was the OG&E Sooner Generating Station modeled?

OG&E is required by the Regional Haze Program to install BART on Unit 1 and Unit 2 (40 CFR 

§ 52.1923). OG&E has committed to meeting the federal emission limit of 0.06 lb/MMBTU by 

January 4, 2019, by controlling Unit 1 and Unit 2 using flue gas scrubbing or by converting the 

units to natural gas. Since the emission reduction will occur sometime in the future, the air 

quality analyses for this facility involved two operating scenarios:

1) Modeling of current actual emissions for Unit 1 & Unit 2; and

2) Modeling of Unit 1 using the BART emission limit and Unit 2 using the maximum 

actual emission rate during 2012 through 2014.

1.3.3 How was the WFEC Hugo Generating Station modeled?

WFEC is required to comply with 40 CFR Part 63, NESHAP, Subpart DDDDD and will install 

an activated carbon injection (ACI) system by April 16, 2016. While there will be a small 

reduction in SO2 emissions resulting from the installation of the ACI, the air quality analysis for 

this facility only involves one operating scenario:

1) Modeling of current actual emissions for Unit 1.

2. WHAT MODELING PROGRAMS WERE USED FOR THE 

MODELING ANALYSIS?

2.1 What is the recommended air dispersion model?

Given the source-oriented nature of SO2, dispersion models are appropriate air quality modeling 

tools to predict the near-field concentrations. For area designations under the 2010 1-hour SO2
Oklahoma 2010 SO2 NAAQS Modeling Report Page 4

primary NAAQS, the AMS/EPA Regulatory Model (AERMOD) was used as outlined in the 

August 23, 2010, clarification memo, “Applicability of Appendix W Modeling Guidance for the 

1-hour SO2 NAAQS.” AERMOD is the preferred air dispersion model, because it is capable of 

handling rural and urban areas, flat and complex terrain, surface and elevated releases, and 

multiple sources (including point, area, and volume sources), to address ambient impacts for the 

designations process.

The AERMOD modeling system includes the following components:

 AERMOD (Version 14134): the dispersion model;

 AERMAP (Version 11103): the terrain processor for AERMOD; and

 AERMET (Version 14134): the meteorological data processor for AERMOD.

Other components that may be used, depending on the application, are:

 BPIPPRIME (Version 04274): the building input processor;

 AERMINUTE (Version 14337): a 1-minute Automated Surface Observing System (ASOS)

winds pre-processor to AERMET;

 AERSURFACE (Version 13016): the surface characteristics processor for AERMET;

 AERSCREEN (Version 14147): a screening version of AERMOD;

2.2 Was screening modeling used?

Screening modeling analyses provide conservative estimates of source impacts with a minimum 

of input. AERSCREEN is the screening model for AERMOD. AERSCREEN will produce 

worst-case estimates of 1-hour impacts for a single source using default meteorological data and 

actual terrain data. Ambient impacts from natural gas fired sources were analyzed using 

AERSCREEN to show that they do not have significant impacts within the domains and 

scenarios modeled.

3. HOW WERE THE MODELING DOMAINS ESTABLISHED FOR THE 

MODELING ANALYSES?

3.1 How were the modeling domains setup?

Domains were assigned to each facility. The modeling domains are centered over the affected 

sources. The following table shows the affected sources, assigned domains, and corresponding 

Oklahoma Mesonet meteorological data site.

Table 3.1-1 Domain ID, Mesonet Site, & Affected Facility

ID Mesonet Site Company Facility

20 Hugo Western Farmers Electric Coop Hugo Generating Station

36 Porter Oklahoma Gas and Electric Muskogee Generating Station

39 Redrock Oklahoma Gas and Electric Sooner Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page 5

Based on EPA guidance, the general guideline for determining the distance between an affected 

source and its maximum ground level concentration is generally 10 times the stack height in flat 

terrain. However, the potential influence of terrain can impact the location and magnitudes of 

significant concentration gradients. The following table shows each emission unit at an affected 

facility, the stack height for the emissions unit, and the expected distance to the expected 

maximum ground level concentration in flat terrain.

Table 3.1-2 Calculated Distance for Maximum Concentration

ID Mesonet 

Site Company/Facility Stack Stack Ht.(ft)

Distance

(km)

20 Hugo WFEC/Hugo Generating Station Unit 1 500 1.52

36 Porter OG+E/Muskogee Generating Station Unit 4 350 1.07

Unit 5 350 1.07

Unit 6 500 1.52

39 Redrock OG+E/Sooner Generating Station Unit 1 500 1.52

Unit 2 500 1.52

Since the maximum impact is expected to be between 0.5 km and 2 km, a domain of 10 km is 

expected to be of sufficient size to determine the ambient air impacts from the affected sources 

unless there is significant terrain. In domains where there is significant terrain (Domain 36), the 

domain was extended to 15 km.

3.2 How were the receptor grids established?

The modeling receptor grid is unique to the particular situation and is dependent on the size of 

the modeling domain, the number of modeled sources, and complexity of the terrain. For the 

purposes of modeling for the 2010 1-hour SO2 designations, receptor placement differs since the 

modeling is acting as a surrogate for monitoring. In areas where it is not feasible to place a 

monitor (water bodies, etc.), receptors were not placed in these locations.

Receptor placement was of sufficient density to provide the resolution needed to detect 

significant concentrations gradients, with receptors placed closer together near the source to 

detect local gradients and placed farther apart away from the source. In addition, receptors were

placed at key locations such as existing monitoring sites (for comparison of modeled 

concentrations to monitored concentrations), sensitive locations (for determining impacts in 

special areas), and along facility fence lines (the ambient air boundary of the affected sources).

The total number of receptors varies based on the specific domain and areas of maximum impact.

For the fine grid, a 100 meter spacing was utilized. The receptor spacing increases as the 

distance from the affected facilities increases. The fine receptor grid was extended out far 

enough to determine the maximum impact from the affected sources. A fine grid extending out 

to 2 km was used to identify the areas of maximum concentration based on the review of the 

stack heights for the affected sources. A generalized rectangular receptor grid for each domain 

was generated using the following:
Oklahoma 2010 SO2 NAAQS Modeling Report Page 6

 Receptors spaced at 100 m along the fence line of the affected sources;

 Receptors spaced at 100 m from the fence line out to 2 km;

 Receptors spaced at 250 m from 2 km out to 3 km;

 Receptors placed at 500 m from 3 km to 5 km; and

 Receptors spaced at 1 km from 5 km out to edge of domain (~10 km).

Aerial photos of the domain with the receptors are included in Appendix A.

Appendix W to 40 CFR Part 51 indicates maximum impacts occur on calm days as the plumes 

encounter hills at or near the same height as the stacks. Terrain surrounding a facility was

evaluated to determine if there were hills in the area at or above stack height and the domain was

extended to include these areas. When high impacts are determined in these areas, a fine grid 

was placed over them to determine the maximum impact.

3.3 What terrain data was utilized for the modeling analyses?

Terrain data was included in all 2010 1-hour SO2 designations modeling analyses. Terrain data 

was obtained from the USGS Seamless Data Server at http://viewer.nationalmap.gov/viewer/. 

The 1/3 arc-second NED data was obtained in the GeoTIFF format for use in AERMAP.

Interpolation of receptor and source heights from the 1/3 arc-second NED elevation data was 

based on the current AERMAP guidance in Section 4.4 of the User’s Guide for the AERMOD 

Terrain Preprocessor (AERMAP) (EPA-454/B-03-0003, 10/2004). AERMAP uses a distance 

weighted bilinear interpolation method.

Oklahoma has three UTM zones (zones 13, 14, and 15). None of the modeling domains for the 

affected sources crossed a UTM zone. All coordinates were based on the North American 

Datum (NAD) 1983 (NAD83).

3.4 What were the domain classifications: rural or urban?

Dispersing plumes encounter more turbulence in urban areas than in rural areas due to building 

wakes as well as warmer temperatures. The higher dispersion in urban areas causes plumes to 

spread more rapidly. The areas of maximum impact in urban areas occur closer to the source.

Determination of whether or not the domain of an affected source should be classified as urban 

or rural was based mainly on land use (the preferred method). However, the urban heat island 

affect was reviewed for those affected sources located in metropolitan areas (OG&E Muskogee).

Determinations of the domain classification are shown below.

Table 3.4-1 Domain Classifications

ID Mesonet Site Company/Facility Urban/Rural

20 Hugo WFEC/Hugo Generating Station Rural

36 Porter OG+E/Muskogee Generating Station Rural/Urban

39 Redrock OG+E/Sooner Generating Station Rural

Aerial photos indicating the area surrounding the facility are included in Appendix B.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 7

4. WHAT SOURCE DATA WAS USED IN THE MODELING 

ANALYSIS?

4.1 What are the affected source configurations and source types?

Accurate characterization of the affected sources is critical to air quality characterization 

utilizing modeling. All of the affected sources are point sources. Stack parameters and facility 

data (building and fence line data) were submitted by each affected facility. The facility data 

was then reviewed and checked for consistency with emission inventory data and aerial images

including location (i.e. latitude and longitude or Universal Transverse Mercator (UTM) 

coordinates and datum) of the emission unit stacks relative to the nearby buildings or structures.

Aerial photos indicating the facility data superimposed onto the aerial photos are included in 

Appendix C.

4.2 What nearby sources were included in the modeling domains?

When determining which sources should be included in the modeling domains for each affected 

source all nearby sources were evaluated. Nearby sources are those sources that are within 20 km of 

the affected sources and that could cause or contribute to a NAAQS violation in the vicinity of the 

affected source. All natural gas fired sources were excluded from the 2010 1-hour SO2 designations

modeling analyses because of the following:

 They do not cause a significant concentration gradient;

 They are not expected to cause or contribute to a NAAQS violation;

 They are represented via the background concentrations.

All other sources of SO2 were included in the 2010 1-hour SO2 designations modeling analyses. A 

list of all sources in the nearby source inventory for each domain is included in Appendix D.

4.3 How were intermittent emission sources addressed?

For area designations under the 2010 1-hour SO2 primary NAAQS, modeling of intermittent 

emissions sources, such as emergency generators and limited intermittent startup/shutdown emissions 

were not included based on the recommendations in the March 1, 2011 memorandum “Additional 

Clarification Regarding Application of Appendix W Modeling Guidance for the 1-hour NO2 National 

Ambient Air Quality Standard.”

4.4 What are the affected source emissions inputs?

For the 2010 1-hour SO2 designations, modeling can be used as a surrogate to ambient 

monitoring to characterize air quality for the designations process. Because designations are 

intended to address current actual air quality (i.e., modeling simulates a monitor), SO2

designation modeling was based on modeling of actual emissions data. Also, since the standard 

is based on a 3 year average, modeling for air quality designations was based on the most recent 

3 years of actual emissions using concurrent meteorological data. Modeling of 3 years of actual 

emissions with concurrent meteorological data is the best representation of the impacts that 

would be monitored in a 3-year monitoring data set.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 8

4.4.1 How were hourly emissions from the affected sources determined?

Actual emission data for input into AERMOD was generated for each affected source. Most 

electric generating units (EGU) have continuous emissions monitoring systems (CEMS). In the 

absence of CEMS data, simply dividing the annual emissions by the number of hours in the year is 

not an accurate representation of actual emissions. For affected sources without CEMS data, actual 

emissions were based on actual throughputs and the calculated SO2 emissions generally based on 

a mass balance. For sources that vary their operation throughout the year, AERMOD input variables 

were used to represent their actual operation throughout the year. Use of AERMOD input variables 

such as hour of day (HROFDY), hour of day and day of week (HRDOW), and monthly hour of day 

and day of week (MHRDOW) were utilized to represent actual operation for those sources without 

CEMS data. Varying emissions were based on the available information such as production logs, 

fuel usage information, operating schedules, etc. CEMS data was used to generate hourly 

emissions files for the affected sources using the following methodology:

Step 1: The emission data was downloaded from the Clean Air Markets Database (CAMD).

Step 2: The monthly data was combined generating annual emission data files for each source at 

an affected facility with CEMS data.

Step 3: The three variables used in an hourly emission file are emissions, velocity, and 

temperature. These hourly values were generated from the CAMD datasets and 

formatted into the units used by AERMOD. The emissions were converted from lb/hr 

values into g/s. The heat input given in the CAMD data was used with Method 19, CO2

concentration, moisture concentration, and stack temperature from recent relative 

accuracy test audits (RATA), to generate the flow rate and resultant velocity. If a unit 

was operating it was assigned the normal stack temperature.

Step 4: The data was then reviewed for continuity and for missing data. If there was a single 

hour of missing data, it was replaced with the average of surrounding non-missing hours. 

If there are periods of missing data with more than a single missing value, operational 

data from the affected facility was reviewed to fill the missing hours.

4.4.2 What operational data was used from the RATA?

The stack parameters used to generate the hourly emission file for AERMOD from the RATA 

are listed below. The values are based on the average of all values recorded during the RATA.

Table 4.3.2-1 Operational Stack Data from RATA

Stack Temp % Moisture % CO2

Station Unit 2012 2013 2014 2012 2013 2014 2012 2013 2014

Hugo Unit 1 313 323 292 11.75 11.80 12.01 12.15 11.81 11.22

Muskogee Unit 4 336 327 320 12.46 13.30 13.51 11.90 11.40 11.76

Unit 5 311 313 315 11.48 12.19 12.00 11.50 11.32 11.40

Unit 6 299 290 294 11.63 11.89 12.46 11.40 11.67 11.48

Sooner Unit 1 305 315 320 10.81 11.11 12.60 11.56 11.20 11.72

Unit 2 312 290 301 11.24 10.47 10.23 11.38 11.70 11.95
Oklahoma 2010 SO2 NAAQS Modeling Report Page 9

4.5 How was GEP stack height addressed?

Good Engineering Practice (GEP) stack height is the minimum stack height needed to prevent 

the stack exhaust plume from being entrained in the wake of nearby obstructions. For the 2010 

1-hour SO2 NAAQS designations process, actual stack heights were used for modeling actual 

emissions rather than following the GEP stack height policy. The GEP stack height policy uses

GEP stack height for stack heights exceeding GEP and actual stack height for stacks below GEP.

The use of actual stack heights in the modeling analysis more closely represents actual ambient 

air quality conditions from the affected sources. Because the purpose of the 2010 1-hour SO2

NAAQS designation modeling is to act as a surrogate for monitoring, if a monitor were located 

in the area around the affected sources, the concentrations detected at the monitor would be 

reflective of the effect of emissions from the actual stack heights of influencing sources.

4.6 Was building downwash included in the modeling analyses?

When one or more structures interrupt the wind flow, an area of turbulence called building 

downwash is created. Pollutants emitted at a fairly low level (e.g., a roof, vent or short stack) 

can be caught in this turbulence, affecting their dispersion. Modeling that includes calculations 

for building downwash gives a more accurate representation of pollutant impacts than does 

modeling that omits consideration of downwash effects.

A building is any physical obstruction to airflow at the modeled facility. A structure is a 

building or group of buildings determined to be important in downwash considerations. The 

dominant downwash structure is the structure that renders the highest GEP recommended stack 

height. If a stack is at GEP or higher, then downwash is not a factor. GEP stack height is 

calculated according to the following equation.

H  h 1.5L

where: H = Recommended stack height.

h = The distance from the highest point on a tier or building to ground level.

L = The lesser of the height or projected width for a particular tier or structure.

Not only are accurate stack parameters important but so are accurate building parameters. 

Building parameters include location and orientation relative to stacks and building size. Other 

parameters include tier heights and coordinates. These parameters are input into BPIP-PRIME to 

calculate building parameters for AERMOD. Affected facilities have submitted information 

regarding buildings located on their property. This data was reviewed and included in the 

modeling analyses.

5. WHAT METEOROLOGICAL DATA WAS USED IN THE 

MODELING ANALYSIS?

5.1 What meteorological data was used?

2012-2014 meteorological data was utilized for the 2010 1-hour SO2 primary NAAQS

designations modeling. The State of Oklahoma utilizes Oklahoma Mesonet surface data, along 
Oklahoma 2010 SO2 NAAQS Modeling Report Page 10

with National Climatic Data Center (NCDC) Integrated Surface Hourly Database (ISHD) surface 

data and National Oceanic and Atmospheric Administration (NOAA) Earth System Research 

Laboratory (ESRL) Global Systems Division (GSD) formerly Forecast Systems Laboratory 

(FSL) Upper Air (UA) data, with all air dispersion modeling. Oklahoma Mesonet data is 

incorporated to help make more accurate forecasts of ambient impacts from the affected sources. 

Use of the Oklahoma Mesonet data also promotes use of more recent, more accurate, and more 

representative data. Processed Oklahoma Mesonet surface data is combined with ISHD surface 

data and ESRL UA radiosonde data using AERMET to produce the surface and profile files used 

by AERMOD. However, if the ISHD station is closer to the facility being modeled and the 

station is an ASOS station with sub-hourly observations, Mesonet data is not utilized with the 

modeling since the ISHD surface data would be more representative.

5.2 What surface data was used?

For each affected source domain a specific meteorological data set was developed based on 

spatial and climatological (temporal) representativeness. The representativeness of the specific 

meteorological data set to the affected source domain was based mainly on proximity and terrain. 

Representativeness of the surface characteristics (albedo, Bowen ratio, and surface roughness)

were also reviewed when assigning a specific metrological data set to an affected source domain.

5.2.1 How were sites from the ISHD evaluated?

There are approximately 83 ISHD automated weather stations in and around Oklahoma that were 

evaluated for combining with Oklahoma Mesonet data to accurately represent the individual 

modeling domains. These stations usually take atmospheric measurements once every hour. 

The ISH data files were downloaded from the NCDC ISHD web site: 

ftp://ftp.ncdc.noaa.gov/pub/data/noaa. Some of the sites are ASOS stations with continuous subhourly values.

The ISH data sites were reviewed for completeness by evaluating the number of hours that were 

recorded at each site. If a specific site contained a significant amount of missing hours, then 

those specific sites were not considered when assigning ISH sites to specific Oklahoma Mesonet 

sites. Since data from the Oklahoma Mesonet is combined with the ISHD data, there is generally 

no need to replace missing values for individual variables. One of the main variables utilized 

from the ISH data is cloud cover (GF1). For each ISHD data file, the specific number of missing 

cloud cover values was also evaluated. If a specific site had a significant number of missing 

cloud cover values, it was also excluded.

5.2.1.1 Was AERMINUTE utilized in the modeling analysis?

The NCDC began archiving 1-minute ASOS wind data (TD-6405), beginning January 2000 for 

first-order NWS ASOS stations, and beginning March 2005 for all other ASOS stations. For 

those ASOS sites, AERMINUTE data was used to incorporate continuous sub-hourly wind data.

The ASOS (6405) files were downloaded and then processed using AERMINUTE. The ASOS 

1-minute files were downloaded from http://www1.ncdc.noaa.gov/pub/data/ for each year and 

applicable ASOS station. There were two ASOS sites (KMKO and KSWO) near the affected 

facilities (OG&E Muskogee and OG&E Sooner) with sub-hourly data.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 11

5.2.2 What is Oklahoma Mesonet data and how is it used?

The Oklahoma Mesonet is a world-class network of meteorological monitoring stations. The 

Oklahoma Mesonet is unique in its capability to measure a large variety of meteorological 

conditions at so many sites across an area as large as Oklahoma. Oklahoma Mesonet data is

provided courtesy of the Oklahoma Mesonet, a cooperative venture between Oklahoma State 

University (OSU) and the University of Oklahoma (OU) and supported by the taxpayers of 

Oklahoma. At each site, the meteorological conditions are continuously measured and packaged 

into 5-minute observations. These 5-minute observations from the Oklahoma Mesonet were 

processed into an AERMET acceptable format. No missing data interpolation was performed for 

the 5-minute data sets.

Specific NCDC ISHD data sites and ESRL UA rawinsonde observation (RAOB) data sites were

assigned to each Oklahoma Mesonet site based on distance and representativeness. Appendix E

lists the Oklahoma Mesonet sites used in the ambient air quality analyses and the assigned 

NCDC ISHD data site and ESRL UA RAOB data site for each Oklahoma Mesonet site. Since 

the NCDC ISHD Station KMKO was closer to the Muskogee modeling domain and is more 

representative than the closest Mesonet Station (Porter) only data from the NCDC ISHD Station 

was utilized when modeling the Muskogee area. Wind roses for the specific domains are

contained in Appendix F.

5.3 What upper air data was used?

The ESRL operates nine RAOB weather stations in and around Oklahoma. These stations 

usually take soundings twice a day. The ESRL data files were downloaded from the ESRL 

RAOB web site: http://esrl.noaa.gov/raobs/.

The UA data was reviewed for missing soundings. A single missing sounding will cause a 

whole day (24 hours) of missing meteorological data values. To reduce the number of missing 

meteorological data, replacement soundings were substituted for the missing soundings. The 

replacement soundings were selected from a site with similar thermodynamic profiles. Each UA 

data station was assigned a primary and a secondary replacement UA station. The primary 

station is basically the station that is closest to the station being reviewed. Each replacement 

sounding was documented.

5.4 How were surface characteristics of the meteorological sites determined?

When using AERMET, to prepare the meteorological data for AERMOD, three surface 

characteristics (Albedo, Bowen Ratio, and Surface Roughness Length) must be determined for 

each surface site. Albedo is the fraction of total incident solar radiation reflected by the surface 

back to space without absorption. Bowen ratio, an indicator of surface moisture, is the ratio of 

sensible heat flux to latent heat flux. Surface roughness length relates the height of obstacles to 

the wind flow and is an important factor in determining the magnitude of mechanical turbulence 

and the stability of the boundary layer. Albedo and Bowen Ratio are used for determining 

planetary boundary layer parameters for convective conditions driven by the surface sensible 

heat flux.

AERSURFACE uses land cover data from the U.S. Geological Survey (USGS) National Land 

Cover Data 1992 archives (NLCD92) to determine the land cover types for a specified location. 
Oklahoma 2010 SO2 NAAQS Modeling Report Page 12

AERSURFACE matches the NLCD92 land cover categories to seasonal values of Albedo, 

Bowen Ratio, and Surface Roughness and then calculates the surface characteristics for input 

into AERMET. NLCD92 data in GeoTIFF format was downloaded from the Multi-Resolution 

Land Characteristics (MRLC) Consortium at the following link: http://www.mrlc.gov/viewerjs/. 

The surface characteristics of the individual domains are included in Appendix G.

5.4.1 What was used to determine the surface moisture conditions?

The monthly rainfall since establishment of the Mesonet program (approximately 20 years) has 

been analyzed for each Mesonet site. The surface moisture conditions (Average, Wet, Dry) for 

each of the Oklahoma Mesonet stations for each month were then determined using the monthly 

rainfall amounts compared to the average rainfall. These determinations were based on the 

guidance contained in the AERSURFACE Users Guide. The Bowen Ratio was then assigned 

based on the monthly surface moisture conditions for each Oklahoma Mesonet station.

6. WHAT BACKGROUND MONITORING DATA WAS USED IN THE 

MODELING ANALYSES?

6.1 What background monitoring data is utilized?

Background concentrations were added to 2010 1-hour SO2 designations modeling analyses. 

Monitoring data was obtained from the EPA air data web site: 

http://www.epa.gov/air/data/index.html. Background concentrations were based on the most 

recent complete year(s) of available monitoring data in the form of the standard indicated below.

Only data meeting the minimum data collection requirements or the minimum percent 

observations were used when determining the design values.

Pollutant Averaging Period Basis of Design Value

SO2 1-hour 3 year average of 99th Percentile 1-hour daily maximum

The inclusion of ambient monitored background concentrations in the model results is important 

in determining the projected cumulative impact of the affected sources and other contributing 

nearby sources impacts. A uniform monitored background concentration based on the monitored 

design values for the latest 3-year period was based on a “regional site” (i.e., a site that is located 

away from the areas of interest but is impacted by similar natural and distant man-made sources). 

All of the monitoring sites in the state of Oklahoma and their related design concentrations are 

shown below.

Table 6.1-1 2012-2014 Monitoring Design Values

Monitor ID County Latitude Longitude Conc.

μg/m3

40-001-9009 Adair 35.75074 -94.66970 39.5

40-071-0604 Kay 36.69727 -97.08130 99.5

40-101-0167 Muskogee 35.79313 -95.30220 129.2

40-109-1037 Oklahoma 35.61413 -97.47510 9.6

40-143-0175 Tulsa 36.14988 -96.01170 100.4
Oklahoma 2010 SO2 NAAQS Modeling Report Page 13

40-143-0179 Tulsa 36.15483 -96.01580 72.0

40-143-0235 Tulsa 36.12695 -95.99890 46.3

40-143-1127 Tulsa 36.20490 -95.97650 36.0

All of the monitoring sites are impacted by large SO2 sources except for the monitor located in 

Oklahoma County. The monitors in Tulsa County are impacted by the Holly Tulsa Refinery and 

the PSO Northeast Power Station. The Monitor located in Muskogee County is impacted by the 

OG&E Muskogee Generating Station and the Georgia Pacific Muskogee Mill. The monitor in 

Kay County is impacted by the Phillips 66 Ponca City Refinery. The monitor in Adair County is 

impacted by the Flint Creek Power Plant. Therefore, the impacts from the Oklahoma County 

monitor were used to represent background impacts from area sources for all modeling domains.

7. WHAT ARE THE MODELED FACILITY IMPACTS?

7.1 What were the modeled impacts for the domain which included the WFEC Hugo 

Generating Station?

The table below shows the results of the air quality analysis for the WFEC Hugo Generating 

Station. The results of the modeling are the three year average of the highest fourth highest

(H4H) daily maximum impact or the three year average of the 99th percentile daily maximum 

impact. The three year average of the H4H daily maximum impact for each of the facilities 

included in the modeling analysis are also listed to show the impacts from each facility on the 

modeling domain. However, the impacts listed do not occur at the same location or at the same 

time as the maximum impact.

Table 7.1-1 Domain 20 Modeling Impacts

Modeled Impact Background Total Impact

Domain Source Group (μg/m3) (μg/m3) (μg/m3)

D20 ALL 108.6 9.6 118.2

HUGO 108.5

IP 2.5

BDM 9.9

Based on the modeling review, the domain would be in compliance with the 2010 1-hour SO2

NAAQS of 75 ppb (196.4 μg/m3based on EPA Reference Conditions, 40 CFR §50.3).

7.2 What were the modeled impacts for the domain which included the OG&E 

Muskogee Generating Station?

The table below shows the results of the air quality analysis for the OG&E Muskogee Generating 

Station. The results of the modeling are the three year average of the H4H daily maximum 

impact. The three year average of the H4H daily maximum impact for each of the facilities 

included in the modeling analysis are also listed to show the impacts from each facility on the 
Oklahoma 2010 SO2 NAAQS Modeling Report Page 14

modeling domain. However, the impacts listed do not occur at the same location or at the same 

time as the maximum impact.

OG&E is required by the Regional Haze Program to install BART on Unit 4 and Unit 5. OG&E 

has committed to meeting the federal emission limit of 0.06 lb/MMBTU by January 4, 2019, by 

conversion of Unit 4 and Unit 5 to natural gas. Since the conversion will occur sometime in the 

future, the air quality analyses for this facility involved three operating scenarios. The future 

operating scenarios were modeled using continuous operation of all the affected emission units.

For Scenario 1:

Actual emissions from CEM data was used for OG&E Unit 4, Unit 5, & Unit 6;

For Scenario 2:

Modeled potential emissions from OG&E Unit 4 using the natural gas fired emission rate 

of 0.0006 lb/MMBTU (which is lower than the BART emission limit of 0.06 lb/MMBTU) and 

projected actual emissions from OG&E Unit 5 & Unit 6 using the 2013 and 2014 two year 

average of the 99th percentile emission rate and heat input shown below. The emission rates and 

heat input from 2012 were not used since they were not representative of future operation.

Table 7.2-1 99th Percentile Emission Factor & Heat Input for OG&E Muskogee Generating Station

2013 2014 Average

Unit lb/MMBTU MMBTUH lb/MMBTU MMBTUH lb/MMBTU MMBTUH

4 N/A 5,669 N/A 6,023 N/A 5,800

5 0.544 5,845 0.576 5,465 0.560 5,655

6 0.549 5,950 0.587 5,939 0.568 5,945

The emission factors and heat input used in the current permit to calculate emissions are listed 

below. These emission factors and heat inputs are below those used for the modeling so the 

emissions used in the modeling should be a conservative analysis of the future air quality.

Table 7.2-2 Emission Factors & Heat Inputs Listed in Permit No. 2005-271-TVR (M-7)

for OG&E Muskogee Generating Station

Unit lb/MMBTU MMBTUH

4 0.53 5480

5 0.51 5480

6 0.53 5150

For Scenario 3:

Potential emissions from OG&E Unit 4 and Unit 5 using the natural gas fired emission 

rate of 0.0006 lb/MMBTU (which is lower than the BART emission limit of 0.06 lb/MMBTU) 

and projected actual emissions from OG&E Unit 6 using the 2013 and 2014 two year average of 

the 99th percentile emission rate and heat input shown above were modeled. The emission rates 

and heat input from 2012 were not used since they were not representative of future operation.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 15

Since the only variables in the domain for the different modeling scenarios were the emissions 

related to the OG&E Muskogee Generating Station, only the overall domain impacts and the 

impacts from the OG&E Muskogee Generating Station are listed for Scenario 2 and 3.

Table 7.2-3 Domain 36 Modeling Impacts Scenario 1

Modeled Impact Background Total Impact

Domain Source Group (μg/m3) (μg/m3) (μg/m3)

D36 ALL 214.0 9.6 223.6

OGE 201.4

GEORG 120.1

DALTIA 1.4

BORAL 56.3

OWENS 49.4

GRDA 23.5

USLIME 3.5

Table 7.2-4 Domain 36 Modeling Impacts Scenario 2 (Potential Future Impacts)

Modeled Impact Background Total Impact

Domain Source Group Units (μg/m3) (μg/m3) (μg/m3)

D36 ALL 179.9 9.6 189.5

OGE ALL 168.7

Unit 4 0.2

Unit 5 115.3

Unit 6 77.6

Table 7.2-5 Domain 36 Modeling Impacts Scenario 3 (Potential Future Impacts)

Modeled Impact Background Total Impact

Domain Source Group Units (μg/m3) (μg/m3) (μg/m3)

ALL 120.1 9.6 129.7

OGE ALL 77.7

Unit 4 0.2

Unit 5 0.2

Unit 6 77.6

Based on the modeling review, the domain would not be able to demonstrate compliance with 

the 2010 1-hour SO2 NAAQS of 75 ppb (196.4 μg/m3based on EPA Reference Conditions) for 

Scenario 1. However, the domain will be able to demonstrate compliance for Scenarios 2 and 3. 

After analyzing the MAXDCONT output files for Scenario 1, it was determined that there were 

113 potential violations at 62 receptors. There are 62 violations based on the H4H, 37 potential 

violations based on the H5H, and 13 violations based on the H6H. There were no additional 

violations after the H6H.

At all 62 receptors, OG&E Muskogee Generating Station was the single largest contributor with 

some contributions from Georgia Pacific Muskogee Mill.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 16

7.3 What were the modeled impacts for the domain which included the OG&E 

Sooner Generating Station?

The table below shows the results of the air quality analysis for the OG&E Sooner Generating 

Station. The results of the modeling provided are the H4H impacts. The maximum impacts for 

each facility included in the modeling analysis are also listed to show the impacts from each 

facility on the modeling domain. However, the impacts listed do not occur at the same location 

or at the same time as the maximum impact.

OG&E is required by the Regional Haze Program to install BART on Unit 1 and Unit 2. OG&E 

has committed to meeting the federal emission limit of 0.06 lb/MMBTU by January 4, 2019, by 

controlling Unit 1 and Unit 2 using flue gas scrubbing or by converting the units to natural gas. 

Since the emission reduction will occur sometime in the future, the air quality analyses for this 

facility involved three operating scenarios.

For Scenario 1:

Actual emissions from CEM data was used for OG&E Unit 1 & Unit 2.

For Scenario 2:

Modeled potential emissions from OG&E Unit 1 using the BART emission limit (0.06 

lb/MMBTU) and projected actual emissions from OG&E Unit 2 using the 2012 through 2014 

three year average of the 99th percentile emission rate and heat input shown below. The emission 

factor for 2013 (0.54) was not used since it was not representative of future operation.

Table 7.3-1 99th Percentile Emission Factor & Heat Input for OG&E Sooner Generating Station

2012 2013 2014 Average

Unit lb/MMBTU MMBTUH lb/MMBTU MMBTUH lb/MMBTU MMBTUH lb/MMBTU MMBTUH

1 N/A 5,455 N/A 5,337 N/A 5,419 N/A 5,405

2 0.715 5,490 --- 5,311 0.708 5,234 0.712 5,345

For Scenario 3:

Potential emissions from OG&E Unit 1 and Unit 2 using the BART emission limit (0.06 

lb/MMBTU) were modeled.

Since the only variable in the domain for the different modeling scenarios is the emissions 

related to the OG&E Sooner Generating Station, only the overall domain impacts and the 

impacts from the OG&E Sooner Generating Station are listed.

Table 7.3-2 Domain 39 Modeling Impacts Scenario 1

Modeled Impact Background Total Impact

Domain Source Group (μg/m3) (μg/m3) (μg/m3)

D39 ALL 127.0 9.6 136.6

OGE 126.8

CONT 33.5

PHILLIPS 1.8
Oklahoma 2010 SO2 NAAQS Modeling Report Page 17

Table 7.3-3 Domain 39 Modeling Impacts Scenario 2 (Potential Future Impacts)

Modeled Impact Background Total Impact

Domain Source Group Units (μg/m3) (μg/m3) (μg/m3)

D39 ALL 152.1 9.6 161.7

OGE ALL 151.8

Table 7.3-4 Domain 39 Modeling Impacts Scenario 3 (Potential Future Impacts)

Modeled Impact Background Total Impact

Domain Source Group Units (μg/m3) (μg/m3) (μg/m3)

D39 ALL 33.9 9.6 43.5

OGE ALL 23.4

Based on the modeling review, the domain would be able to demonstrate compliance with the 

2010 1-hour SO2 NAAQS of 75 ppb (196.4 μg/m3based on EPA Reference Conditions) for 

Scenario 1. In addition, the impacts for Scenarios 2 and 3 demonstrate of compliance with the 

2010 1-hour SO2 NAAQS. The impacts for Scenario 2 are higher than the impacts for Scenario 

1 since the emissions are based on projected heat input for Unit 2 and projected lb/MMBTU.

Also, Scenario 2 represents continuous operation of both units.

8. WHAT IS THE SUMMARY OF THE MODELING RESULTS?

8.1 What areas demonstrate compliance with the 2010 1-hour SO2 NAAQS using 

modeling?

The areas surrounding the WFEC Hugo Generating Station and the OG&E Sooner Generating 

Station can demonstrate compliance with the 2010 1-hour SO2 NAAQS using the modeling.

8.2 What areas do not currently demonstrate compliance with the 2010 1-hour SO2

NAAQS using modeling?

While the modeling air quality analysis under Scenario 1 for the area surrounding the OG&E 

Muskogee Generating Station does not demonstrate compliance with the 2010 1-hour SO2

NAAQS, the modeling air quality analyses under Scenarios 2 and 3 do demonstrate compliance

with the 2010 1-hour SO2 NAAQS. The federally enforceable BART reductions reflected in 

Scenarios 2 and 3 are to be achieved by January 4, 2019.

Current ambient monitoring data indicates compliance with the 2010 1-hour SO2 NAAQS. The

predicted impacts at the monitoring site using modeling do not correlate well with the ambient 

monitoring data which raises questions regarding meteorological data representativeness. 

Additional studies of the modeling analyses should be conducted to examine the issues related to 

correlation of predicted modeling impacts and actual monitor impacts. Also, additional 

meteorological data (e.g. on-site), which is more representative of the modeling domain, should 

be collected to generate modeling which accurately represents the area impacted by the OG&E 

Muskogee Generating Station.
Oklahoma 2010 SO2 NAAQS Modeling Report Page 18

8.2.1 What area has potential impacts greater than the 2010 1-hour SO2 NAAQS 

that were predicted under Scenario 1 for the OG&E Muskogee Generating Station?

The area with the modeled impacts greater than the 2010 1-hour SO2 NAAQS are encompassed

within a single Township (Township 15N, Range 19E) in Muskogee County. The two largest 

SO2 sources in Muskogee County are also located within this township. The two largest SO2

sources in Muskogee County and the area with modeled impacts greater than the 2010 1-hour 

SO2 NAAQS are contained within eight sections of Township 15N, Rage 19E: Sections 15 (NE 

Corner), 16 (NW Corner), 21, 22, 27, 28, 33 (SW Corner), and 34 (SE Corner). The area with 

predicted impacts greater than the 2010 1-hour SO2 NAAQS are contained within a small area 

within two sections of Township 15N, Rage 19E: Section 15 (80%) and Section 16 (20%).

9. WHAT REFERENCES WERE USED?

 Additional Clarification Regarding Applicability of Appendix W Modeling Guidance for

the 1-hour NO2 NAAQS (March 1, 2011);

o http://www.epa.gov/ttn/scram/guidance/clarification/Additional_Clarifications_Appe

ndixW_Hourly-NO2-NAAQS_FINAL_03-01-2011.pdf

 Guidance Concerning the Implementation of the 1-hour SO2 NAAQS for the Prevention of 

Significant Deterioration Program (August 23, 2010);

o http://www.epa.gov/region07/air/nsr/nsrmemos/appwso2.pdf

 Applicability of Appendix W Modeling Guidance for the 1-hour SO2 NAAQS (August 23, 

2010);

o http://www.epa.gov/ttn/scram/guidance/clarification/ClarificationMemo_AppendixW

_Hourly-SO2-NAAQS_FINAL_08-23-2010.pdf

 SO2 NAAQS Designations Modeling Technical Assistance Document (December 2013);

o http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/SO2ModelingTAD.pdf

 Guidance for 1-Hour SO2 NAAQS SIP Submissions (September 22, 2011);

o http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/DraftSO2Guidance_9-22-11.pdf

 User’s Guide for the AMS/EPA Regulatory Model - AERMOD

o http://www.epa.gov/ttn/scram/models/aermod/aermod_userguide.zip.

 User’s Guide for the AERMOD Meteorological Data Preprocessor (AERMET)

o http://www.epa.gov/ttn/scram/7thconf/aermod/aermet_userguide.zip.

 AERMINUTE User’s Instruction

o http://www.epa.gov/ttn/scram/7thconf/aermod/aerminute_14337.zip.

 AERSURFACE User’s Guide

o http://www.epa.gov/ttn/scram/7thconf/aermod/aersurface_userguide.pdf.
Appendix A – Facility Domains with Receptors
Oklahoma 2010 SO2 NAAQS Modeling Report Page A-1

WFEC – Hugo Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page A-2

OG&E – Muskogee Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page A-3

OG&E – Sooner Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix B – Land Use/Land Cover Aerial Photos
Oklahoma 2010 SO2 NAAQS Modeling Report Page B-1

WFEC – Hugo Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page B-2

OG&E – Muskogee Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page B-3

OG&E – Sooner Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix C – Aerial Photo Overlaid With Facility Data
Oklahoma 2010 SO2 NAAQS Modeling Report Page C-1

WFEC – Hugo Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page C-2

OG&E – Muskogee Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report Page C-3

OG&E – Sooner Generating Station
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix D – Source Data
Oklahoma 2010 SO2 NAAQS Modeling Report Page D-1

Domain 20 Source Data

Source ID Facility Easting Northing Elevation Stk Ht Stk Temp Velocity Stk Dia SO2

(m) (m) (m) (ft) (°F) (fps) (ft) (lb/hr)

UNIT 1 WFEC – Hugo 839782.8 3769894.6 147.1 500.0 260 47.00 26.0 2,391.03

PLT761

BDM Eng 834500.0 3780048.7 156.3 25.0 160 96.67 3.0 8.98

IPBRKBLR International Paper 859439.4 3768633.0 151.3 246.0 133 42.60 11.0 4.62

IPPRBLR International Paper 859435.2 3768628.3 151.2 296.0 439 88.80 14.5 8.55

IPNRFN International Paper 859499.9 3768626.1 152.5 296.0 439 88.80 14.5 32.60

IPLIMEKILN International Paper 859486.6 3768587.3 152.6 148.0 469 44.70 5.8 0.36

1

- Emissions from the plant were limited based on operational data from the facility. The emissions were limited using the Seasonal Hour Day of Week 

emission factor command (SHRDOW). Emissions from this facility were limited to Spring, Summer, and Fall; Monday through Friday; between the 

hours of 9 a.m. and 5 p.m. The actual average number of hours operated from 2012-2014 were 550 hours per year with a maximum of 950 hours in a 

single year.
Oklahoma 2010 SO2 NAAQS Modeling Report Page D-2

Domain 36 Source Data

Easting Northing Elevation Stk Ht Stk Temp Velocity Stk Dia SO2

Source ID Facility (m) (m) (m) (ft) (°F) (fps) (ft) (lb/hr)

UNIT 4 OG&E Muskogee 293116.7 3959729.8 156.2 350.0 264 44.96 24.0 2,010.98

UNIT 5 OG&E Muskogee 293172.0 3959739.3 156.8 350.0 264 41.80 24.0 1,912.21

UNIT 6 OG&E Muskogee 293240.4 3959757.7 157.0 500.0 264 55.01 21.5 2,206.57

DAL20 Dalitalia 284208.4 3953784.7 171.2 46.3 130 29.80 4.95 0.11

DAL23 Dalitalia 284164.9 3953711.7 170.8 46.0 130 45.08 2.70 0.05

DAL29 Dalitalia 284093.8 3953787.7 171.0 51.3 130 24.10 5.36 0.09

BORSCRUB Boral 282161.2 3951159.0 183.5 70.0 355 36.29 6.2 43.60

GPSTACK1 Georgia Pacific 292555.0 3956494.1 161.9 260.0 353 28.46 10.0 85.33

GPSTACK3 Georgia Pacific 292594.0 3956513.0 162.0 260.0 306 28.24 13.8 412.56

OBFURNA Owens Brockway 288620.7 3960596.6 179.6 150.0 918 29.16 5.3 9.30

OBFURNB Owens Brockway 288656.6 3960582.4 180.0 80.0 389 28.89 7.1 18.61

M1 US Lime 334096.8 3940641.2 203.6 150.0 266 57.09 5.3 20.31

K1 US Lime 334000.6 3940571.3 204.5 96.0 155 31.20 7.0 0.17

UNIT 1 GRDA 294138.0 4007357.0 189.5 504.0 300 68.14 20.0 2,881.26

UNIT 2 GRDA 294211.0 4007262.0 188.8 507.0 190 90.98 20.0 922.97
Oklahoma 2010 SO2 NAAQS Modeling Report Page D-3

Domain 39 Source Data

Easting Northing Elevation Stk Ht Stk Temp Velocity Stk Dia SO2

Source ID Facility (m) (m) (m) (ft) (°F) (fps) (ft) (lb/hr)

Unit 1 OG&E Sooner 674572.1 4036106.8 286.1 500.0 264 60.05 20.0 2,012.10

Unit 2 OG&E Sooner 674497.9 4036137.0 286.2 500.0 264 59.04 20.0 1,841.85

TO4 Continental Carbon 672587.8 4059257.6 293.2 213.3 1817 159.90 7.0 447.12

TO12 Continental Carbon 672416.8 4059290.6 293.4 150.0 1671 109.00 11.5 629.15

TO3 Continental Carbon 672538.8 4059261.6 293.6 150.0 1601 104.00 9.5 340.00

NO.4FCC Phillips Refinery 671244.4 4062452.8 300.7 175.0 423 81.30 4.5 1.12

NO.5FCC Phillips Refinery 671146.1 4061061.4 307.0 175.0 147 46.30 8.5 8.24

FLARESP Phillips Refinery 671369.5 4060672.6 301.0 199.0 1832 65.30 3.0 1.02

FLARECC Phillips Refinery 670807.4 4061307.2 301.3 150.0 1832 65.60 2.5 10.63

FLAREEP Phillips Refinery 671187.6 4062248.4 296.1 245.0 1832 65.60 2.5 3.13

B0008 Phillips Refinery 670832.1 4061973.3 304.6 162.0 336 12.60 8.0 1.43

B9/B10 Phillips Refinery 670828.5 4062066.5 304.9 89.0 305 31.80 11.8 1.85
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix E – 2012-2014 Oklahoma Mesonet Sites & Associated ISH & ESRL Stations
Oklahoma 2010 SO2 NAAQS Modeling Report Page E-1

Oklahoma Mesonet Sites & Associated ISH & ESRL Stations

STID NAME/City COUNTY LAT LONG ELEV SFCS LAT LONG ELEV USAF # UAS LAT LONG

HUGO Hugo Choctaw 34.0308 -95.5401 175 KHHW134.0314 -95.5398 177.7 720559 FWD 32.80 -97.30

PORT2Porter Wagoner 35.8257 -95.5598 193 KMKO 35.6577 -95.3658 183.5 723556 OUN 35.23 -97.47

REDR Red Rock Noble 36.3559 -97.1531 293 KSWO 36.1624 -97.0893 293.8 723545 OUN 35.23 -97.47

1

- KHHW started on 2/2012, replaced 2011 with data from KPRX.

2

- KMKO is closer to the Muskogee area and is an ASOS station with sub-hourly wind data and is more representative of the Muskogee area. Therefore, the 

PORT Mesonet data was not utilized in the modeling analyses.

Abbreviations

STID – Oklahoma Mesonet Station ID;

LAT, LONG – Latitude and Longitude in NAD83;

ELEV – Elevation is in meters;

SFCS – ISH Surface Station Call Identifier;

UAS – Upper Air Station Call Identifier.
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix F – Wind Roses
Oklahoma 2010 SO2 NAAQS Modeling Report Page F-1

2012-2014 Hugo Wind Rose
Oklahoma 2010 SO2 NAAQS Modeling Report Page F-2

2012-2014 KMKO Wind Rose
Oklahoma 2010 SO2 NAAQS Modeling Report Page F-3

2012-2014 Porter Wind Rose
Oklahoma 2010 SO2 NAAQS Modeling Report Page F-4

2012-2014 Red Rock Wind Rose
Oklahoma 2010 SO2 NAAQS Modeling Report

Appendix G – Surface Characteristics
Oklahoma 2010 SO2 NAAQS Modeling Report Page G-1

Domain 20 Surface Characteristics

HUGO Albedo AVG Wet Dry Surface

Winter 0.18 0.81 0.43 1.95 0.022

Spring 0.15 0.40 0.26 1.12 0.039

Summer 0.18 0.53 0.32 1.37 0.142

Fall 0.18 0.81 0.43 1.95 0.142

KHHW

Winter 0.18 0.81 0.43 1.95 0.022

Spring 0.15 0.40 0.26 1.12 0.039

Summer 0.18 0.53 0.32 1.37 0.144

Fall 0.18 0.81 0.43 1.95 0.144

KPRX

Winter 0.18 0.72 0.40 1.91 0.016

Spring 0.14 0.34 0.22 1.04 0.023

Summer 0.19 0.47 0.29 1.31 0.039

Fall 0.19 0.72 0.40 1.91 0.032

KAQR1

Winter 0.18 0.84 0.42 1.90 0.044

Spring 0.15 0.44 0.26 1.14 0.092

Summer 0.18 0.47 0.29 1.14 0.189

Fall 0.18 0.84 0.42 1.90 0.189

1

– 2011 Run
Oklahoma 2010 SO2 NAAQS Modeling Report Page G-2

Domain 36 Surface Characteristics

Albedo AVG Wet Dry Surface

PORT

Winter 0.18 0.73 0.39 1.77 0.026

Spring 0.15 0.36 0.23 1.01 0.042

Summer 0.18 0.45 0.28 1.16 0.183

Fall 0.18 0.73 0.39 1.77 0.183

KMKO

Winter 0.18 0.72 0.41 1.94 0.016

Spring 0.14 0.33 0.22 1.03 0.023

Summer 0.19 0.50 0.30 1.42 0.037

Fall 0.19 0.72 0.41 1.94 0.031

0167

Winter 0.17 0.64 0.37 1.47 0.021

Spring 0.14 0.37 0.24 0.93 0.027

Summer 0.18 0.43 0.28 1.01 0.064

Fall 0.18 0.67 0.37 1.47 0.064
Oklahoma 2010 SO2 NAAQS Modeling Report Page G-3

Domain 39 Surface Characteristics

REDR Albedo AVG Wet Dry Surface

Winter 0.19 0.87 0.46 1.77 0.014

Spring 0.17 0.37 0.26 1.01 0.050

Summer 0.18 0.65 0.35 1.16 0.112

Fall 0.18 0.87 0.46 1.77 0.112

KSWO

Winter 0.19 0.91 0.48 2.00 0.017

Spring 0.16 0.47 0.31 1.18 0.051

Summer 0.18 0.63 0.37 1.54 0.095

Fall 0.18 0.91 0.48 2.00 0.095